Sign Up for Swamplot Emails:

Comment of the Day: Floating Homes for Houston

COMMENT OF THE DAY: FLOATING HOMES FOR HOUSTON “I’m a ship designer with 20+ years of experience and I will say that a float-off house is absolutely feasible from a technical point of view. A quick check in the used barge market shows that you can get something house-sized (80 ft. by 30 ft.) for $65,000. Of course building something on-site would cost a lot more than construction in a shipyard. Not sure how this compares to what a foundation costs. But you’d need to add in some kind of anchoring system so that your house doesn’t float away when it floods. And permitting would be a whole other kettle of fish. I’m available for moonlighting if any architect wants to investigate this for a client!” [Orang Bodoh, commenting on Where Are Houston’s Floodwater-Ready Homes]

13 Comment

Nice. Just one question: how do you control a floating house?
.
Actually another question: presumably the floatation system for the house is styrofoam of some sort? Can that be designed to double as rigid insulation?

Something in the 30×80 range would be pretty close to the foot print on a 50′ or 60′ lot — I’d bet you could build that with reasonably nice finish out and a secured foundation at around $100/SF- but you’d need to tack on another $20-$30/SF for the lot cost.

Not exactly an affordable solution ($130/SF is a fairly nice production house in Houston) but you’re in the ballpark at least. Biggest problem to solve is how your MEP works when your house elevation is constantly changing.

I didn’t flood this time. All those idiots who bought inside the flood plain and flooded need to stop whining. Oh wait, you didn’t buy in a flood plain either? Well, maybe this city has serious problems that need to be discussed.

The simplest means of securing a floating house would be via a spud – just a pole or two embedded in the ground that the house rides up and down on. Google “spud barge” to see what this looks like. The spuds could be incorporated into the design as a visual element.
.
But I think you’d need to use something with more strength than styrofoam for the hull. A house can’t have a perfect weight distribution; there will be heavy spots and light spots, so you need rigidity to make sure it floats without breaking. In my world we’d use steel but it could be aluminum or probably even fiberglass. You could fill it with insulation if you wanted, but there would need to be some means of inspection so that you’d be certain it would float when the floods come.

Detachable utility hookups are easy and low-tech, used on all sorts of RVs and travel trailers. Scale it up and you’re done. What if the owner/occupant forgets to disconnect? Build in a failure point to the line so that it breaks predictably in a way that can easily be repaired.
.
But even still…okay, so maybe you can buy used barges for prices that appear on the surface to be good enough, and maybe that’d work for somebody that has the time, money, and know-how. I wouldn’t even be especially surprised if somebody hadn’t already done this in some swampy flood-prone place in rural Louisiana or Texas. But manufacturing them from scratch or repairing and retrofitting them with the built-in structural support for rigidity and so on, yeah that’s going to be damned expensive.
.
I have to ask, what’s wrong with stilts?

Amphibious Retrofits Recommended for Flooded Homes: All homes and structures that were flooded from Hurricanes Harvey and Irma should be retrofitted with modular amphibious concrete foundations. Amphibious retrofits are a realistic and practical way to make structures – single family homes and modest-size commercial structures – flood-resilient at all levels of floodwater, for both the near term and decades hence. Homes with amphibious foundations typically sit close to ground level. These foundations look like and replace conventional foundations. With the arrival of floodwaters, the buoyant foundation and its above structure gradually rises straight up along its corner underground “telescoping vertical guideposts” – up 20 feet or higher as needed, floating and well-stabilized on the floodwater’s surface. As floodwaters recede, the structure and its foundation gently settles back down to its original ground-level footing. Overseas, these foundations have gone through years of repeated flooding and are well-proven.

The modular foundations typically consist of an assembly of airtight/watertight marine concrete pontoons which are post-tensioned together to form a monolith foundation that is secured to the underside of the home or structure. The structure must be partially raised so that the original foundation can be replaced or modified in order to slide in the incoming amphibious foundation. Each concrete pontoon encapsulates an environmental-friendly Styrofoam-type buoyant material (expanded polystyrene-EPS) to provide “floatation redundancy” that makes the entire structure 100% unsinkable. The telescoping guideposts are usually placed in the ground out of sight at or under the corners of the amphibious foundation; they prevent any lateral movement to the home or structure while it is floating. The maintenance-free concrete foundations can carry 50-year warranties, some longer. Such foundations are relatively economical to construct; they cost less than 50% of the cost of FEMA’s traditional flood-resilience solution, i.e., expensively elevating structures up 12-18 ft. on many piles. Industry-proven coiled umbilical cords connect all local utilities. High-density polyethylene (HDPE) pontoons can be used in certain situations, as can spud/telephone-pole-type guide posts; concrete provides more stability and telephone pole guide posts are obtrusive-looking.

Amphibious foundations are generally not suitable for buildings which are located in V-Flood Zones or are directly exposed to large open ocean waves or exceed 3 or 4 floors. Otherwise, any structure which can be partially raised is suitable to be retrofitted. Since amphibious foundations and structures are generally not addressed under traditional building codes, some flexibility will be needed from local building officials. (In 2014, senior FEMA officials acknowledged in a series of emails that “amphibious retrofits” were acceptable within FEMA’s construction and design parameters, but such was never publicized.)

Amphibious foundations and retrofits are practically unheard of in the U.S. However, a couple dozen do-it-yourself/homemade amphibious retrofits have been attached under fishing-camp structures in Old River Landing in Pointe Coupee Parish, Louisiana. For a couple of decades now, these amphibious foundations/structures have been successfully rising and falling every year with Mississippi flood waters.

Urban Waterfront Advisors, Inc. (917-697-4719) is prepared to advise, organize and implement any or all of the above for any neighborhoods or communities who strongly desires such. Up to 80-pages of additional details and photos are available electronically upon request (scottwholcombe@urbanwaterfrontadvisors.com).